The Pacifica Department of Public Works was at the scene since about 7 a.m.
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Pacifica Department of Public Works officials told ABC7 News they knew this might happen, so they had large eight to 10 ton boulders on standby not too far from the area.
Crews have been filling the sinkhole all day with the boulders.
They are trying to preserve whatever material is still underneath the promenade as a temporary solution. "We're going to reassess the condition and come up with a final design on how to fix this," Pacifica Department of Public Works Director Van Ocampo said.
"They're all pretty excited, so they wanted to come out here once they heard there was a digger moving rocks putting dirt in the hole," Pacifica resident Eric Moessinger said.
The hole is about 40 feet long by eight feet wide.
This is a problem for the city, but it has been a lot of fun for spectators in the area.
Not great for the city but fun to watch for some families out here pic.twitter.com/aqNXNiScfu— Melanie Woodrow (@MelanieWoodrow) January 18, 2016
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